问题补充:
The rescuers to work as soon as they arrived at the spot of the accident.
A. set out
B. set off
C. set up
D. set in
答案:
(答案→)A. set out
B. set off
C. set up
D. set in
解析:句意:救援人员一到出事地点,就开始工作了。使用:Set out to do sth.开始着手做…, B. set off成分,引发,引爆, C. set up建立,D. set in嵌入,所以选A。